Editors of scientific literature rely heavily on peer reviewers to evaluate the integrity of research conduct and validity of findings in manuscript submissions. The purpose of this study was to describe the ethical concerns of reviewers of nursing journals. This descriptive cross-sectional study was an anonymous online survey. The findings reported here were part of a larger investigation of experiences of reviewers. Fifty-two editors of nursing journals (six outside the USA) agreed to invite their review panels to participate. A 69-item (...) forced-choice and open-ended survey developed by the authors based on the literature was pilot tested with 18 reviewers before being entered into SurveyMonkeyTM. A total of 1675 reviewers responded with useable surveys. Six questions elicited responses about ethical issues, such as conflict of interest, protection of human research participants, plagiarism, duplicate publication, misrepresentation of data and ‘other’. The reviewers indicated whether they had experienced such a concern and notified the editor, and how satisfied they were with the outcome. They provided specific examples. Approximately 20% of the reviewers had experienced various ethical dilemmas. Although the majority reported their concerns to the editor, not all did so, and not all were satisfied with the outcomes. The most commonly reported concern perceived was inadequate protection of human participants. The least common was plagiarism, but this was most often reported to the editor and least often led to a satisfactory outcome. Qualitative responses at the end of the survey indicate this lack of satisfaction was most commonly related to feedback provided on resolution by the editor. The findings from this study suggest several areas that editors should note, including follow up with reviewers when they identify ethical concerns about a manuscript. (shrink)